Radial piston hydraulic engine

ABSTRACT

The invention concerns a radial piston hydraulic engine ( 10 ), which includes a rotated box section ( 11 ), with which box section ( 11 ) a cam ring ( 12 ) is connected. The radial piston hydraulic engine ( 10 ) includes a fixed non-rotary shaft ( 14 ), with which a cylinder body ( 15 ) in a fixed position is connected. The radial piston hydraulic engine includes a distributor ( 13 ), which is connected with the box section ( 11 ) and rotates together with it, whereby through channels located in the distributor a pressurized medium is conducted to pistons ( 16   a   1   , 16   a   2  . . . ) of cylinders (P 1 , P 2  . . . ) controlled by the distributing valve, that is, by distributor ( 13 ), and that at least some cylinders (P 1 , P 2  . . . ) include in connection with themselves a shut-off valve ( 70   a   1   , 70   a   2  . . . ) which is used to make some pistons ( 16   a   1   , 16   a   2  . . . ) inoperative. Shaft ( 14 ) includes in the same cylinder-block (I) at least two control pressure channels (Y 1 , Y 2 ) for the shut-off valves ( 70   a   1   , 70   a   2 ) of its cylinder body ( 15 ), whereby by supplying pressure selectively into a channel (Y 1  or Y 2 ; Y 1  and Y 2 ) it is possible to make certain cylinders (P 1 , P 2  . . . ) inoperative by directing control pressure to the shut-off valves ( 70   a   1   , 70   a   2   , 70   a   3  . . . ).

[0001] This invention concerns a radial piston hydraulic engine.

[0002] Such radial piston hydraulic engine solutions are known in thestate of the art, wherein a box section is rotated and to the boxsection is joined a distributor mounted to the same. The distributor isa so-called distributing valve, which includes borings made in thedirection of the distributor bushing and opening from the distributor'send face. There are inlet channels to the distributor and outletchannels from it. The inlet channels open in the distributor's end face,as do the outlet channels. The respective channels of the distributingvalve are alternately in connection with piston spaces, which pistonspaces include pistons and pusher wheels connected with the pistons andadapted to move against a cam ring located in connection with the boxsection. Under these circumstances, some pistons are in the work stageand some are not. Those pistons which are in the work stage are suppliedwith a pressurised medium through the distributor's channels and,correspondingly, those pistons which have bypassed the work stage removeoil through the distributor by way of the outlet channels of thedistributor. The pusher wheels located in the pistons push against thecam ring located in the box section. The cam ring includes a wavelikeshape, whereby the cam ring and the box section connected to it arerotated with the aid of the pusher wheels. To ensure optimum operationof the distributor, the distributor's end face must be in a tight slidefit against that end face of the cylinder body wherein the channelsleading to the piston spaces are located.

[0003] The application presents an improvement especially on thesolution presented in the applicant's earlier FI 942304 application. Thestructure according to the invention is especially concerned with such aradial piston hydraulic engine, wherein the cylinder body and the shaft14 are immovably connected to one another, e.g. by a groove coupling,and in which structure the cylinder body and its associated shaft arenon-rotary. In accordance with the invention, those cylinder spaces P₁,P₂ . . . of the cylinder body, which are connected with cylinder block1, in connection with themselves include oil channels, which are furtherconnected with the distributor in the end face of the cylinder body. Insome of these cylinder body channels shut-off valves are located, whichare controlled by pressure. According to the invention, the shut-offvalves are pre-controlled as follows. A channel boring is made throughthe shaft, and from the boring in question a control is branched offinto certain cylinder spaces and into the shut-off valves located inconnection with these. The structure according to the invention includesat least one other boring, from which controls are branched off to otherpiston spaces of the cylinder block and into their shut-off valves. Someof the channels connected with cylinder spaces in the cylinder body aresuch which do no include shut-off valves, and pressurised oil is alsoconducted to these in operation. Thus, by using the control channelsselectively, different connections and thus different combinations ofvolume flows are achieved.

[0004] The radial piston hydraulic engine in accordance with theinvention is characterised in that which is stated in the claims.

[0005] The invention will be described in the following by referring tosome preferable embodiments of the invention, which are shown in thefigures of the appended drawings, however, to which the invention is notintended to be exclusively limited.

[0006]FIG. 1 is a cross-sectional view of the radial piston hydraulicengine according to the invention.

[0007]FIG. 2 illustrates the use of channels Y₁ and Y₂ located in shaft14 in order to bring about control of the shut-off valves located in thecylinder body.

[0008]FIGS. 3A and 3B show a ½revolution volume regulation implementedin a radial piston hydraulic engine according to the invention whichincludes 12 cylinders. FIG. 3A is a cross-section of the radial pistonhydraulic engine, and FIG. 3B is a section I-I of FIG. 3A. Regulationvariations are shown in corresponding sections I-I in FIGS. 4, 5A and5B.

[0009]FIG. 4 shows so-called ¼revolution volume regulation.

[0010]FIG. 5A shows so-called ¾revolution volume regulation.

[0011]FIG. 5B shows the {fraction (1/1)}revolution volume regulationposition.

[0012]FIG. 6A shows a distributing valve 100 connected to channels Y₁and Y₂ used to direct the control pressure supply to channels Y₁ and/orY₂. A shut-off valve 70 located in the cylinder body is connected withone channel Y₁ to illustrate the operation of the shut-off valve.

[0013]FIG. 6B shows shut-off valve 70 on a larger scale.

[0014]FIG. 1 is a cross-sectional view of radial piston hydraulic engine10. The radial piston hydraulic engine 10 includes a rotated box section11. A cam ring 12 is connected to box section 11. In the embodimentshown in the figure, box section 11 is rotated, to which box section adistributor 13 is connected, which is in a fixed position in relation tobox section 11. Distributor 13 is a distributing valve including severalborings e_(1A); e_(2B), which are in connection with the inlet channele₁ and with the outlet channel e₂ of a central shaft 14. Distributor 13rotates with the box section 11, and the pressurised channels e_(1A) andreturn oil channels e_(2B) are brought alternately into contact with thechannel ends of those flow channels of cylinder pistons 16 a ₁, 16 a ₂ .. . located in cylinder body 15, which lead to the cylinder spaces ofcylinders P₁, P₂ . . . . Under these circumstances, some of the pistons16 a ₁, 16 a ₂ . . . of cylinders P₁, P₂ . . . are in the work stage,whereby pressurised medium is conducted through distributor 13 tocylinders P₁, P₂ . . . and some pistons 16 a ₁, 16 a ₂ . . . are in theidle stage, whereby oil is conducted from the cylinder spaces of thecylinders P₁, P₂ . . . of the said pistons 16 a ₁, 16 a ₂ . . . throughdistributor 13 to outlet channel e₂. The non-rotary cylinder body 15located in the non-rotary central shaft 14 includes a cylinder block R₁,whereby cylinder body 15 contains several cylinder spaces P₁, P₂ . . .and pistons 16 a ₁, 16 a ₂ . . . in these. Piston 16 a ₁, 16 a ₂ . . .is adapted to move in the cylinder space of cylinder P₁, P₂ . . . underthe influence of the oil pressure supplied thereto. As shown in thefigure, each piston 16 includes a pusher wheel 17 a ₁, 17 a ₂ . . . witha circular cross-section and placed freely on its top surface. Whenpushing piston 16 a ₁, 16 a ₂ . . . forcefully against the wavelikesurface 12 a of cam ring 12, cam ring 12 and the connected box section11 and the distributing valve, that is distributor 13, connected withbox section 11 are made to rotate.

[0015] Box section 11 is pivoted to rotate supported by bearings G₁ andG₂ in relation to the central shaft 14.

[0016] As shown in FIG. 1, the cylinder body in connection with thepiston spaces includes pressure-controlled shut-off valves 70 a ₁, 70 a₂ . . . , whereby by using the shut-off valves 70 a ₁, 70 a ₂ . . . itis possible to shut off the supply of pressurised oil to the cylinderspaces of cylinders P₁, P₂ . . . and thus to remove from operation thepiston connected with the cylinder space in question. The volume flow ofthe engine can be regulated by directing the supply of control pressureto the shut-off valves 70 a ₁, 7 a ₂ . . . located in the cylinder body.

[0017] The radial piston hydraulic engine shown in FIG. 1 includes achannel Y₁, through which control pressure is conducted to shut-offvalves 70 a ₁, 70 a ₃, 70 a ₅, 70 a ₇, 70 a ₉ and 70 a ₁₁, whichshut-off valves are further connected with cylinders P₁, P₃, P₅, P₇, P₉and P₁₁. Correspondingly, oil channel Y₂ is connected with shut-offvalves 70 a ₂, 70 a ₆ and 70 a ₁₀ to turn off or to turn on theoperation of pistons P₂, P₆, P₁₀ connected with the said cylinders.

[0018] Cylinders P₄, P₈ and P₁₂ do not in connection with themselvesinclude shut-off valves 70, whereby they are always in operation. Thus,the radial piston hydraulic engine in accordance with FIG. 1 preferablyin the cylinder block includes a total of 12 cylinders; cylinders P₁, P₂. . . P₁₂. The number of cylinders P₁, P₂ . . . may also be a multipleof 12.

[0019]FIG. 2 illustrates the control operation of shut-off valve 70 a ₁,70 a ₂ . . . so that through control channel Y₁ a control pressure isconducted to the shut-off valve in order to close it. Channel Y₁ opensinto ring space 51, into which ring space also open e.g. the controlchannels of shut-off valves connected with six different pistons. Thus,by letting pressure affect in channel Y₁ shut-off valves 70 a ₁, 70 a ₃,70 a ₅, 70 a ₇, 70 a ₉ and 70 a ₁₁ are controlled at the same time andthe flow path to cylinders P₁, P₃, P₅, P₇, P₉ and P₁₁ is closed for thepressurised medium at its operating pressure. Correspondingly, throughthe other channel Y₂ control pressure can be conducted into the otherring space 61 and further, as illustrated in the figure, to threedifferent shut-off valves 70 a ₂, 70 a ₆, 70 a ₁₀ , which are located inthe cylinder body in connection with the oil channel leading tocylinders P₂, P₆, P₁₀.

[0020] Correspondingly, to some cylinders P₄, P₈, P₁₂ pressurised oil isconducted directly from distributor 13 in such a way that there is noshut-off valve in connection with the channels of the concerned cylinderspaces.

[0021] In this way, by using control into channels Y₁ and/or Y₂ shut-offvalves 70 a ₁, 70 a ₂ . . . can be controlled and an operating pressureis obtained for the desired cylinders P₁, P₂ . . . When there are 12pistons, the following volume flow combinations of ¼, ½, ¾and 1revolution volume are obtained.

[0022]FIGS. 3A and 3B show ½revolution regulation. FIG. 3B is a sectionI-I of FIG. 3A. The cylinder block includes 12 cylinders, cylinders P₁,P₂ , P₃ . . . P₁₂. FIG. 3 shows darkened cylinders P₁, P₃, P₅, P₇, P₉and P₁₁, which are in connection with channel Y₁, whereby a controlpressure is conducted to channel Y₁. Cylinders P₁, P₃, P₅, P₇, P₉ andP₁₁ are divided equally by 600 in relation to one another in thecylinder block.

[0023] Cylinders P₂, P₆, P₁₀ in connection with channel Y₂ are dividedby 120° in relation to one another. Those cylinders which do not inconnection with themselves include any shut-off valve in the cylinderbody are also divided by 120° in relation to each other in the cylinderblock R₁, and the cylinders in question are indicated by referencenumbers P₄, P₅ and P₁₂ in FIG. 3.

[0024] The figure indicates a so-called ½revolution volume regulation,wherein a pressure is supplied into channel Y₁. Cylinders P₁, P₃, P₅,P₇, P₉ and P₁₁, are closed and an operating pressure can be conducted toall other cylinders of the cylinder block, that is, to cylinders P₄, P₈and P₁₂ and to cylinders P₂, P₆, P₁₀. Thus, six cylinders are operatingand the other six are closed.

[0025]FIG. 4 shows so-called ¼revolution volume regulation. Hereby thecontrol pressure is supplied both through channel Y₁ and through channelY₂, whereby the cylinders P₁, P₃, P₅, P₇, P₉ and P₁₁ connected tochannel Y₁ are closed and, correspondingly, cylinders P₂, P₆, P₁₀connected to channel Y₂ are closed. Instead, cylinders P₄, P₈ and P₁₂,which have no shut-off valve 70 connected to them, are operating.

[0026]FIG. 5A shows so-called ¾revolution volume regulation. In theregulation position concerned, a control pressure is supplied intochannel Y₂ and thus to cylinders P₂, P₆, P₁₀. Hereby the said cylindersare in the closed state, whereas cylinders P₁, P₃, P₅, P₇, P₉ and P₁₁ aswell as cylinders P₄, P₈ and P₁₂ are operated.

[0027] When no control pressure is conducted into channel Y₁ or intochannel Y₂, all cylinders P₁, P₂ . . . P₁₂ are connected to operate anda so-called full revolution volume regulation position is obtained. Thesaid regulation position is shown in FIG. 5B.

[0028]FIG. 6A shows an embodiment of the control according to theinvention. In accordance with the invention, a distribution valve 100 isused, which includes control pins 101 a ₁, 101 a ₂. The pins can beaffected with a control oil pressure or, for example, electrically byusing a solenoid. By affecting the pins, a pressure connection withchannels Y₁ and Y₂ is opened and closed. Distribution valve 100 may belocated in a fixed position on the end of shaft 14 or it may be a partof shaft 14.

[0029] In the solution shown in FIG. 6A, an operating pressure isconducted to valve 10 through its channel 102. By affecting control pins101 a ₁ and 101 a ₂ at their ends N₁, N₂ on the pressure side, the pinsare moved towards the end of pin space 104 a ₁, 104 a ₂ and a connectionfor the pressurised medium is opened through channel 102 to channels Y₂and/or Y₁. When no control is supplied electrically or hydraulicallyinto pressure spaces N₁, N₂ at the pin ends, the pins will remain insuch a position with the aid of springs J_(a), J_(b) located around thepins, which allows a passage for the pressurised medium from controlchannels Y₂, Y₁ through outlet lines 103 a ₁, 103 a ₂ to the engine'soutlet line.

[0030]FIG. 6B shows the structure of shut-off valve 70 on a largerscale.

[0031] As is shown in FIGS. 6A and 6B, control pressure is thusconducted into channels Y₁ and/or Y₂ . As is further illustrated in thefigures, the said pressure is conducted to shut-off valve 70 in such away that it will affect the end face of pin 80 of the shut-off valve. Inthe normal state, the end face of pin 80 is affected by spring 3, whichholds the said shut-off valve 70 in the closed position, when nooperating pressure has been conducted to the other side of the pin, andallows oil to flow to outlet F₁₀, for example, to the box sectionthrough the central channel F of pin 80. When the pressurised oilaffects on the side of spring J of pin 80, the operating pressure is noteither able to move the pin 80, and pin 80 will close the passage forthe operating pressure to the cylinder P₁ or P₃ or P₅ . . . , which isin connection with shut-off valve 70. When no control pressure issupplied, for example, to channel Y₁ as is shown in FIG. 6B, andoperating pressure affects the end face of pin 80, the operatingpressure moves pin 80, as is indicated by arrow S₁ in the figure, to theright and the operating pressure can affect piston 16 a ₁, 16 a ₃ . . .Hereby the connection to outlet F₁₀ through the central channel F of pin80 is closed at the same time. When the operating pressure is effective,it moves pin 80 to the left (arrow S₂) as shown in the figure, and thepiston space of the cylinder opens to outlet channel F₁₀ through thecentral channel F of pin 80. The spring J is intended to move pin 80into such a position that the oil space located below the piston will beconnected to the outlet at a time when the engine is not under pressure.

[0032] When no control pressure is supplied through channels Y₁ and/orY₂ to pin 80 of shut-off valve 70 and when the operating pressure hasmoved pin 80 in the direction indicated by arrow S₁ and has opened apassage for the operating pressure to the space below the piston, thepressure existing in the work cycle in question in the space below thepiston with shut-off valve 70 in the said position will keep pin 80pressed in direction S₁. This is the case also when the rotateddistributor 13 distributes oil to the different work steps and inbetween connects the oil space below piston 16 a ₁, 16 a ₂ . . . withoutlet channel e_(2B), e₂ through distributor 13.

1. Radial piston hydraulic engine (10), which includes a rotated boxsection (11), with which box section (11) a cam ring (12) is connected,and which radial piston hydraulic engine (10) includes a fixednon-rotary shaft (14), with which a cylinder body (15) is connected in afixed position, whereby the radial piston hydraulic engine includes adistributor (13), which is connected with the box section (11) androtates together with it, whereby through channels located in thedistributor a pressurised medium is conducted to the pistons (16 a ₁, 16a ₂ . . . ) of the cylinders (P₁, P₂ . . . ) under the distributingvalve's, that is, the distributor's (13) control, and that at least somecylinders (P₁, P₂) include a shut-off valve (70 a ₁, 70 a ₂ . . . ) inconnection with themselves, which is used for making some pistons (16 a₁, 16 a ₂ . . . ) inoperative, characterised in that the shaft (14)includes in the same cylinder block (I) at least two control pressurechannels (Y₁, Y₂) for the shut-off valves (70 a ₁, 70 a ₂) of thecylinder body (15), whereby by supplying a pressure selectively into thechannel (Y₁ or Y₂; Y₁ and Y₂) certain cylinders (P₁, P₂ . . . ) can bemade inoperative by supplying control pressure to the shut-off valves(70 a ₁, 70 a ₂, 70 a ₃ . . . ).
 2. Radial piston hydraulic engine asdefined in claim 1 , characterised in that channels (Y₁, Y₂) are inconnection with a distributing valve (100), which includes control pins(101 a ₁, 101 a ₂), which are used to regulate the supply of pressurisedmedium selectively into channels (Y₁ or Y₂; Y₁ and Y₂) in order tocontrol the shut-off valves (70 a ₁, 70 a ₂ . . . ) of the cylinder body(15) in connection with them.
 3. Radial piston hydraulic engine asdefined in claim 1 or 2 , characterised in that the channel (Y₁, Y₂) isa boring in shaft (14) in connection with such a ring channel (51, 61)in the outer periphery of shaft (14), which is in connection withcertain shut-off valves (70 a ₁, 70 a ₂, 70 a ₃ . . . ) of the cylinderbody (15).
 4. Radial piston hydraulic engine as defined in any one ofthe preceding claims, characterised in that the shut-off valve (70 a ₁,70 a ₂, 70 a ₃ . . . ) includes a spring (3), which is used to press theshut-off valve towards one extreme position of a pin (80) (in directionS₂), in which extreme position an oil space located below piston (16 a₁, 16 a ₂ . . . ) is connected with an outlet channel (F₁₀) through acentral channel (F) in pin (80).
 5. Radial piston hydraulic engine asdefined in any one of the preceding claims, characterised in thatcontrol pressure of hydraulic oil from channel (Y₁, Y₂) is conducted tothat end face of pin (80), which includes a spring (3).
 6. Radial pistonhydraulic engine as defined in any one of the preceding claims,characterised in that the control pressure distributing valve (100)located in connection with channels (Y₁, Y₂) is connected with shaft(14).
 7. Radial piston hydraulic engine as defined in the precedingclaim, 15 characterised in that the distributing valve (100) isconnected with one end of shaft (14).
 8. Radial piston hydraulic engineas defined in claim 1 , characterised in that the radial pistonhydraulic engine includes 12 cylinders (P₁, P₂ . . . P₁₂).
 9. Radialpiston hydraulic engine as defined in claim 1 , characterised in thatthe radial piston hydraulic engine includes N×12 cylinders (P₁, P₂ . . .P_(N)), that is, a multiple of
 12. 10. Radial piston hydraulic engine asdefined in claim 8 , characterised in that channel (Y₁) conducts thehydraulic oil to those shut-off valves (70 a ₁, 70 a ₃, 70 a ₅, 70 a ₇,70 a ₉ and 70 a ₁₁), which are connected with cylinders (P₁, P₃, P₅, P₇,P₉ and P₁₁).
 11. Radial piston hydraulic engine as defined in claim 8 ,characterised in that channel (Y₂) conducts the hydraulic oil to thoseshut-off valves (70 a ₂, 70 a ₆, 70 a ₁₀), which are connected withcylinders (P₂, P₆, P₁₀) of the cylinder body (15).
 12. Radial pistonhydraulic engine as defined in claim 8 , characterised in that cylinders(P₄, P₈ and P₁₂ ) do not in connection with themselves include anyshut-off valve (70), whereby pressurised oil is supplied fromdistributor (13) to the concerned cylinders (P₄, P₈ and P₁₂) at alltimes.